"""to use this for modifying behavior of the Python command line, put this in
   your $HOME/.bash_profile or equivalent:
    PYTHONSTARTUP=$HOME/.pythonrc.py
   also make a symlink to Python as 'pysh':
    ln -s /usr/bin/python ~/bin/pysh

   to reconstruct a script from the history:
    cp ~/.pyhistory newscript.py
   edit it to keep the lines you want, and also put at the beginning:
    #!/path/to/pysh
    from user import *

   to run the script:
    pysh newscript.py
"""
import os, sys, readline, atexit
histfile = os.path.join(os.environ['HOME'], '.pyhistory')
if os.path.split(sys.executable)[-1] == 'pysh':
 from glob import glob
 sys.ps1 = '$ '
 sys.ps2 = '> '
 DATASTACK = []
 def sysstacker(value = None):
  index = readline.get_current_history_length()
  item = readline.get_history_item(index)
  readline.replace_history_item(index - 1, 'qpush(%s)' % item)
  qpush(value)
  print >>sys.stderr, DATASTACK
 sys.displayhook = sysstacker
 def systrapper(exctype, value, traceback):
  index = readline.get_current_history_length()
  item = readline.get_history_item(index)
  command = item.split()
  fullpath = which(command[0])
  if fullpath:
   if os.path.isdir(fullpath) and len(command) == 1:
    readline.replace_history_item(index - 1, 'os.chdir(%s)' % repr(item))
    os.chdir(fullpath)
    print >>sys.stderr, 'current working directory now: %s' % os.getcwd()
    sysstacker()
   else:
    command[0] = fullpath
    readline.replace_history_item(index - 1, 'piperun(%s)' % repr(command))
    result = piperun(command)
    sysstacker(result)
   sys.exc_clear()
  else:
   sys.__excepthook__(exctype, value, traceback)
 sys.excepthook = systrapper
 # file operations
 def ls(arg = '*'):
  return glob(arg)
 def which(command):
  for path in os.getenv('PATH', '').split(':'):
   fullpath = os.path.join(path, command)
   if os.path.exists(fullpath):
    return fullpath
 # stack operations
 def push(arg):
  DATASTACK.append(arg)
 def qpush(arg):
  if arg is not None:
   push(arg)
   if isinstance(__builtins__, dict):  # a dict when run as a script
    __builtins__['_'] = arg
   else:  # it's a module
    __builtins__._ = arg
 def pop(arg = -1):
  return DATASTACK.pop(arg)
 def drop(arg = -1):
  DATASTACK.pop(arg)
 def swap():
  DATASTACK[-2], DATASTACK[-1] = DATASTACK[-1], DATASTACK[-2]
 # uncategorized
 def piperun(command):
  pipe = os.popen(' '.join(command))
  result = map(str.rstrip, pipe.readlines())
  pipe.close()
  return result
else:
 import inspect
try:
 readline.read_history_file(histfile)
except IOError:
 pass
atexit.register(readline.write_history_file, histfile)
if os.path.split(sys.executable)[-1] != 'pysh':
 del os, sys, readline
del histfile, atexit